Geothermal is not renewable

You can group geothermal plants into two types:

• The kind that pump water underground and take steam or hot high pressure water out.
• The kind that drill holes in the ground and use conduction to get heat out.

Admittedly, I don't know a great deal about geothermal systems, but I do understand heat flow reasonably well. And geothermal systems are all about heat flow. Here are the problems that I see:

Conduction is an impractical way to move utility-scale amounts of heat through anything but the thin walls of a heat exchanger. For instance, ground temperatures typically rise about 3 C for every 100 meters you go underground. Ground conductivity is about 1.5 watts/meter/kelvin. Multiply those two and get 45 kW/km^2. Remember that utility-scale power means you need hundreds of megawatts of heat. Bottom line: geothermal isn't renewable. It works by cooling down some chunk of rock in place, rather than by converting heat that rises from the earth's core.

You might think that a big hunk of rock can provide a lot of heat for a very long time. For instance, a cubic kilometer of granite, cooling 30 C, provides 2 gigawatt-years of heat. Figure 20% of that gets converted to electricity. Over 30 years, that cubic kilometer of granite will run a 13 megawatt power plant. We're going to need dozens of cubic kilometers.

You might think that dozens of cubic kilometers would be cheap. Ranch land out in Idaho goes for $360,000/km^2. Assuming you can suck the heat out of a vertical kilometer of rock, the 13 megawatts from that ground are going to bring you a present value of $90 million. Sounds great!

But wait... before you get started, you are going to have to shatter that cubic kilometer of rock so you can pump water through it to pick up the heat. The hydrofracking folks have learned quite a lot about getting fluid out of tight underground formations. I think the useful comparison to make is the value of the fluid extracted. Oil is worth $100/barrel right now, which is $850/m^3. Water from which we will extract 30 C of heat to make electricity at 4 cents a kilowatt-hour at 20% efficiency is worth 28 cents/m^3, ignoring the cost of capital to convert the heat to electricity. There is a factor of 3000 difference in the value of that fluid. Now hydrofracking rocks for heat doesn't have to be as thorough as hydrofracking them for oil, since you can count on ground conduction to do some work for you. But I don't think the difference is going to save a factor of 3000 in the fracking cost.

So, that means geothermal is going to be confined to places where the rock is already porous enough to pump water through. Like the Geysers in Northern California, which is a set of successful gigawatt geothermal plants. I think it's interesting that the output has been declining since 1987.

The problem is thought to be partial depletion of the local aquifer that supplies the steam, because steam temperatures have gone up as steam pressures have dropped. This sounds right to me, but I'll point out that the water in the aquifer is probably sitting in a zone of relatively cool rock which has hotter rock above it. As the aquifer has drained, the steam has to travel through more rock, causing more pressure drop, and thus less steam transport. Where water used to contact rock, steam does now, pulling less heat from the rock, so that the rock face heats up from conduction from hotter impermeable areas.

Wait... how did cool rock end up under hotter rock? The 150 or so gigawatt-years of heat that have been pulled out of the 78 km^2 area over the last 50 years have probably cooled a kilometer stack of rock by about 30 C (or maybe a thinner layer of rock by a larger temperature swing). I'm not at all convinced by the USGS claim that the heat source is the magma chamber 7km down. Assuming the magma surface is at 1250 C (the melting point of granite) and the permeable greywacke is at 230 C, a 78 km^2 area 6 km thick will conduct about 20 megawatts, an insignificant fraction of the energy being taken out.

Refilling the aquifer will help pull heat out of the shallower rock, but that's not going to last decades. To keep going longer they'll need to pull heat from deeper rock, and that's going to require hydrofracking the deeper greywacke.

And that's expensive.

Wicked

Just read "Wicked: the Life and Times of the Wicked Witch of the West". This after we saw Wicked in London as part of our summer Europe trip. My cousin Christopher plays the drums and various other percussion pieces in that production.

The musical is a blast. We had great seats, the music and singing were fabulous, the staging sometimes overwhelming, the kids loved it, Chris showed us around a little bit... what fun.

When we got back, we got the music, and now the kids have mostly memorized all the songs. It's slightly disturbing seeing my 4 year old singing "No one mourns the wicked".

Martha got the book out of the library, and we both read it. Like all tragedies, it's frustrating. It's a vastly more complex and subtle story than the musical. If you're reading this but haven't read the book or seen the musical, see the musical first, as it'll be tough to enjoy after the book. And don't read the rest of this post.

SPOILERS.

Like most things that I really like, I wanted the book to be better. In particular, a good tragedy should make me feel the inertia of doom, the sense that the characters are carrying themselves towards their downfall. In the book, there was definitely some of that, but I also got the feeling that doom was coming in the form of spunky little Dorothy Gale, and that the characters were bending their wills to the needs of that other story arc. So that wasn't as impressive. And why the hell couldn't a smart girl like Elphaba convert the tactical (and unsuspected) advantage of being able to fly on a broom into a way to pick off the wizard and his chief lieutenants.

The part that I really liked was how Elphaba's desire to do good was a significant part of what drove her to her doom. I find myself strongly agreeing with the idea that the desire to do good is not good in itself, and can actually lead to evil. If you want to be good you have to actually *do* it.

But there were so many things to love about the book. The dialog, the political machinations, tictocism, Elphaba's reaction to Dorothy asking for the forgiveness that Elphaba herself had been denied... I love reading an author who has insights way past my own.

Ouch

Ed Lu gave a talk at Google today on his B612 foundation.

He mentioned that the asteroid that caused the K-T extinction was probably 10 miles in diameter, um hummm.... which meant that the top had not yet entered the bulk of the atmosphere when the bottom hit the ocean. That image really got me.

The speed of sound through granite is 5950 m/s, which is substantially less than the speed of an incoming asteroid. Things in low earth orbit go at about 7800 m/s, and Ed said incoming asteroids are around 3-4 times that. So that means that when the asteroid smacks into the earth, there is a really good chance that the back of the asteroid will hit the earth before the shock wave gets to it -- it'll punch all the way into the Earth surface. Koeberl and MacLeod have a nice table here which shows a granite on ice impact needs only 6 km/s vertical velocity to punch all the way in (they neglected water as a target material, an odd oversight since the majority of the earth is covered in water, more or less a solid at these velocities). If the incoming velocity is 25 km/s, which is on the low side of what Ed suggested, then anything striking within 76 degrees of vertical is going all the way in. It seems to me that most impacts would be like that.

So after the impact, most of the energy is added to stuff below the ground surface. That's 1e25 joules for the K-T asteroid. Enough to melt 5e18 kg of rock, which is 100 times as much mass as the asteroid itself. Figure a small fraction of that will vaporize and the whole mess goes suborbital.

For the next hour you have thousands of trillions of tons of glowing molten lava raining down on everything. Everything that can burn (6e14 kg of carbon in the world's biomass) does so, promptly.

And this asteroid impact thing has actually happened, many times. As Ed says, it's like pushing Ctrl-Alt-Del on the whole world.

Side notes: There is 1e18 kg of oxygen in the atmosphere, far more than necessary to burn every scrap of biomass on earth. The story I read was that the oxygen in the atmosphere came from plants. If so, there must be a lot of carbon buried somewhere: 8.6e14 kg of known coal reserves are less than 1%.

Another interesting point, vis-a-vis ocean fertilization: there is about as much carbon in the atmosphere as in the world's biomass. We'd have to boost the productivity of 1/10 of the world's ocean by a factor of 8, from existing productivity (125 gC/m^2/year), to fix the CO2 problem in the atmosphere in 15 years. Ocean CO2 would take a century or more. That productivity boost is like converting that much ocean into a coral reef! This seems like a lot to me.

Do powerplants use too much water?

Coal and nuclear powerplants make heat, convert some of that to electriciy, and reject the rest. They use water, and lots of it, to reject the heat.

The USGS says that thermoelectric powerplants (nearly all coal and nuclear) use 49% of the water withdrawn in the US. That sounds like a lot, and it is. It's also misleading.

92% of the water used by powerplants is used for once-through cooling. That means they suck water from the river, use it to cool their condensers, then pump it back the river at somewhat higher temperature. There are legal limits to the temperature they can send back out, and as the intake water temperature rises closer to those limits, they have to pump more water, and eventually shut down the powerplant. This has happened, famously, in France during a heat wave, right when everyone wanted to run their air conditioners.

The other 8% of the water used by powerplants is used in recirculating cooling. In these systems water is used to cool the condensers, but then some of that water is evaporated in those familiar hyperbolic cooling towers, which cools the rest, and the water is cycled around. These systems use a lot less water because they only need to make up the water that evaporates. Of that 8%, about 70% is evaporated and 30% returned to the lake or river it came from.

Since 1990, the US has mostly built gas-turbine powerplants. These reject heat in the form of incredibly hot jet exhaust, and don't need water. But they burn natural gas which has caused us to send our plastics industry to China. I don't think many people appreciate how dumb that was.

New nuclear plants in the US will be either on the coastline or evaporatively cooled, because there is no appetite for increasing the amount of once-through freshwater cooling. And I don't think there will be many evaporatively cooled plants at either greenfield or brownfield sites: Greenfield evaporatively cooled plants require new water rights which are very difficult to secure. Brownfield replacements of older coal fired powerplants will be difficult because nuclear plants are much bigger than older coal plants, reject a lot more heat, and so need a lot more water, getting back to the new water rights problem. That leaves new PWR development for areas with a lot of water (US southeast) and coastlines. [Edit: And any new coastline PWR developments are going to face new hurdles as a result of Fukushima.]

Water rights are one reason why I'm so interested in molten salt reactors. MSR cores and turbines run at higher temperatures than those of pressurized water reactor cores, so they can be air cooled without killing their efficiency (and thus jacking up their costs a lot). Air cooling is a good thing because it removes an entire class of regulatory problems, and thus an entire kind of project risk.

Deep Ocean O2 Used by Gulf Oil Spill

About 150 million gallons of oil have spilled into the Gulf. Estimates vary, but something like 50 to 100 million gallons of that oil are now dispersed into the water. Bacteria are supposed to "break down" that oil. What does that mean?

It means they will oxidize the oil. On average, oil has two hydrogen atoms to one carbon atom. CH2 + 1.5O2 => CO2 + H2O, so consuming 14 grams of oil requires 48 grams of oxygen. So, that means that consuming e.g. 50 million gallons of oil requires 150,000 metric tons of oxygen.

The oxygen concentration of the sea is around 7 mg/kg. So, 150,000 metric tons of oxygen is all the oxygen in 22 cubic kilometers of seawater. 22 cubic kilometers in the Gulf of Mexico is approximately one drop in a 5 gallon bucket.

Bottom line: there is plenty of oxygen, even at depth, to oxidize all the oil spilled.

Lanthanum Phosphate

As you know, I've built this nice new pool. The pool is designed to stay at 85 F for most of the year, and so it has solar panels in their own insulated glass boxes so that it can collect heat even when the outside air temperature is low. Because those panels can get ridiculously hot (338 F) in the sun when water is not flowing through them, they are made of copper rather than plastic as is more commonly done. I've been learning the consequences of that difference.

A couple weeks after filling the pool I added chlorine (hypochlorous acid, HClO), which immediately caused a brown stain on my nice white plaster pool. Copper from the panels had leached into the pool water in the form of copper ions. The HClO oxidized those ions, probably to Cu2O, which promptly came out of solution and bound to the plaster. So, now I have a brown pool. It really pissed me off for a while, but I've grown used to the look and now I actually think it looks good in some places. One of the interesting side effects of having all this copper in the water is that the copper is antimicrobial. The pool has often gone for days with zero chlorine, at 92 F, and with tons of phosphate, and has essentially no algae growth. Without copper that would be a recipe for an algae bloom.

I have these little strips that claim to test the copper content of the water, and that test result drops to zero shortly after I add chlorine. After four or five days it will bounce back up to 0.5 ppm (ppm meaning mg/liter in this case). That means my 38500 gallon pool has 2.5 ounces of copper in it that used to be on the roof. Clearly I can't go on like this for too long, or I'm going to have pinhole leaks in the roof panels. Happily, I've noticed recently that the copper seems to be zero even after a few days of no chlorine, and if this is real, it means the copper has stopped leaching into the water, perhaps because I now have a protective patina on the interior of the pipes.

In my various attempts to keep my white plaster white, I added "chelating agents" to the pool. These things are basically dish soap, and load the water with lots of phosphate (HPO4 2-). The idea is that the phosphate ion will preferentially bind to the copper ions and form Cu3(PO4)2, which is insoluble in water. Presumably this copper phosphate doesn't bind to the plaster but instead can be filtered out. In combination with a low pH this was supposed to reduce the Cu2O in the plaster, then convert it to Cu3(PO4)2, but if that was happening it sure wasn't obvious. I eventually gave up. This exercise left the pool with over 2500 ppb phosphate, which is way too high. When the copper levels recently stopped going up without chlorine, an interesting thing happened: algae! So this weekend I determined that it was time to take out that phosphate.

One takes out phosphate by adding Lanthanum Chloride. This reacts with the phosphate to make LaPO4, which immediately comes out of solution and forms this white fluffy stuff on the bottom of the pool. I tried vacuuming this up -- big mistake. The stuff will plug any filter, instantly. I tried a few times adding lots of DE to the filter, and gave up. That's when I read online that you have to vacuum this stuff out of your pool entirely, just dumping the water to the street. Then I realized I hadn't really plumbed my pool with an option to vacuum to waste. D'oh!

[Update: fixed the plumbing so I can now pump to the street or sewer. Since I have very low-resistance pipes, it looks like I can pump over 80 gallons/minute to the street, which is very impressive to see.]

For a little while I was feeling pretty beaten. The phosphate levels weren't reading any lower, the pool was a mess, I had no plan to get it clean, and my fingernails were gone from cleaning the DE out of the backwash tank. This Lanthanum Phosphate is amazing -- a tiny amount turns DE into a watertight membrane, something like Bentonite clay.

Then I got back to work. I pumped the water out of the spa, then set the valves to bypass both the filter and backwash tank, suck from the pool and return to the spa. With my vacuum in place I was vacuuming the pool into the spa. Before turning on the pump I put a sump pump in the spa and pumped it out into a hose which went to the sewer. Yes, this was pumping phosphates into the city's sewer. I think I pumped out about 2.5 pounds of phosphate, or about one box of dishwashing detergent. I had no copper in the water, nor any chlorine, and my pH was 7.5. It shouldn't be a problem for anything downstream. The vacuum sucked everything off the bottom and we dumped about 800 gallons of water, or $2.40. Even better, my phosphate is now down to 300 ppb, which isn't perfect but it's nice to be out of the unmeasurable range.

In doing the research for this blog post I found out that my tap water already has around 190 ppb phosphate in it, added by Los Altos to control corrosion in copper pipes. So, I need to measure my copper levels now that I have low phosphate to see if I'm back into corroding my solar panels. Hopefully something else is protecting the panels.

Also, I've learned that the patina that can protect copper is soluble in ammonium salts. That's significant because ammonia in the pool is what you measure when you measure "combined chlorine" (really chloramines). It seems I'm going to have to stay on top of that, not just because chloramines are smelly eye irritants, but because the stuff attacks my panels.

I can keep after it with adding chlorine, but my main line of defense was supposed to be a nightly dose of ozone, intended to burn anything organic down to N2, CO2, and water. The ozone is on hold until I can re-cover my DE filter grids in stainless steel mesh, instead of the polypropylene mesh they have now. Meh. More work. Some other weekend.

[Update: stainless steel mesh won't hold diatomaceous earth. I got some mesh samples and tried pouring DE mud on them, and it fell right through. Under the microscope, it's clear that DE grains are just tens of microns across, and so a macroscoping mesh isn't going to do it.

I've read that glass is compatible with ozone, so I'm going to try fiberglass as a filter material to hold the DE, and we'll see how that goes.]

[Update2: BGF fiberglass filter fabric style 421 style 580 holds diatomaceous earth just fine. I had to hand sew it with stainless steel wire, since fiberglass strands are completely useless for sewing, as they fray and break at the slightest provocation. Next up: long term test of fiberglass grid covering to see if it breaks or does some other bad thing.]

A Great Day

Today my dad and I took my daughter Anya to an event hosted by the UC Berkeley Nuclear Engineering group. I got my BA at Berkeley, and my dad was a post-doc there in what was then called the Nuclear Chemistry group. It was great fun showing Anya around a small portion of the campus where I spent nearly seven years.

We started with lunch and about half an hour of Frisbee on Memorial Glade. After that, Anya (7 years old) spent three consecutive hours in 6 classrooms listening to and participating in discussion and demonstrations about radioactivity and nuclear power.

Anya spent probably 20 minutes of that wriggling around in her seat and the rest of the time she was engaged. The presentations were perfect for someone her age. The students doing the presentations were energetic and interesting. We got to see the old reactor room in Etcheverry Hall which now houses a bunch of interesting experiments. I got to meet a bunch of other parents, and it was fabulous to talk with other people who don't freak out when they discover that every home's smoke detector has a little bit of Americium-241 which sends the Geiger counter up several orders of magnitude once you get it close enough that the air isn't shielding it. (Pop - pop - pop - bzzzzzzzeeeeeeee)

Afterwards Anya and I walked around campus some more, watched some students learning to walk on a tightrope, and then went out to dinner together at Zachary's Pizza. For most of the hour long drive home we talked about how to design an "earth-friendly" town -- things like arranging the houses around a central area for the kids to plan in, building at the edge of but not in a forest, etc.

So, basically, I had a perfect day.

Pumping pool water

I've been looking into the costs of pumping water through the filters and valves and pipe work around the pool, and it's quite interesting. For context, you need to understand that we live in California, in the San Francisco Bay Area (known to our utility PG&E as area X). That means that we're going to be using the pool 9 months a year, and the marginal electricity we'll be using for the pool will cost us $0.424 to $0.497 per kilowatt-hour (Those are the charges for >24.2 kWh/day and >36.3 kWh/day). That sounds like a lot of money, and it's going to sound worse as you read below.

In 1997, marginal electricity with a basic residential rate was $0.122/kWh, so the average cost growth since then is 10.0% per year. That's substantially faster than the discount rate of 6% per year that I usually apply to future money. If the cost growth of energy exceeds the discount rate into the future, it means that the energy I spend to pump pool water 10 years from now will cost more in current dollars than the energy I spend today.

You can't extrapolate a growth curve indefinitely into the future, and the price of electricity in current dollars cannot rise without limit. That said, I'm fairly confident that over the next 40 years the price of electricity will at least keep up with a 6% discount rate. That means that I'm predicting that the electricity the pumps burn 40 years from now costs me just as much, today, as the electricity that the pumps burn today.

I want to compare the costs of running the pool with the cost of building it, so I can make decisions about what sort of equipment to install. In the face of electricity that does not discount into the future, I have to put some sort of time limit on how long the pool will be operated. I'm going to pick 40 years. At that point my grandkids are likely to have learned to swim, and there is an about even chance that I'll be dead and won't have to worry about money any more. Over 40 years (9 months a year), each kilowatt-hour burned, per day, costs a total of $4643 in 2010 dollars. The bottom line is that, had I built my new pool in a standard fashion, the electricity to run it would have cost over $150,000 in present value. That's more than the pool! Instead, I've spent a few thousand dollars improving the efficiency of the plumbing so that my projected present value cost is more like $40,000 (which can be improved further).

Those of you with astronomical electricity bills, and pools, may be wondering how did I do that?

Let's get started with a simple result that is relatively new for the residential pool industry: slower is better. If I run a pump at 42 GPM for 16 hours, it'll turn over about 40,000 gallons. If, instead, I run the pump at 84 GPM for 8 hours, it'll move the same number of gallons. However, and this is really important, the pump has to push about twice as hard to move water twice as fast. Power is pressure times flow, so pumping twice as much water up twice the pressure head takes 4 times as much flow power. 4x the power in half the time is 2x the energy, and energy is what you pay for. Bottom line: slow the pump down.

You should also get the most efficient pump possible. If you don't have solar and so don't need variable head, and can mount the pump below the level of the water surface, then get something like a Sequence 5100. Otherwise get an Intelliflow 4x160, which is what I got.

Slower-is-better isn't the complete answer, because of variable pump efficiency and in-line spring-loaded valves. So most pools won't run their pumps 24 hours a day, as I do.

Note that I talked about flow power in the paragraph above. Flow power is pressure (e.g. psi) times gallons per minute. Try it. Most pumps turn electricity into flow power with an efficiency that varies between 15 and 50%. 15% is the efficiency at low speeds (right before the pump stalls and efficiency goes to zero), and 50% is the efficiency at something near top speed. Variable-speed pumps, like the Intelliflow 4x160, usually hit their maximum efficiency at high RPM settings and high flow rates (but I include a counterexample in my spreadsheet link below). As a result, when you run the pump more slowly, less energy is required to move the water, but the pump takes more electricity to produce each joule of flow energy. You can see the pump power and head curves for the 4x160 on page 47 of the user's manual. And I've extracted the numbers off the chart and done efficiency calculations here. Bottom line: best efficiency is at 30 GPM for a normal pool. I'll be forced up to 42 GPM (at a measured 31% efficiency) because the pool is big.

The analysis gets a little complicated because most pools have in-line spring loaded valves, which should be banned. Many solar installations suggest a check valve between the filter and the water line going up to the roof, because the panels drain at the end of the day and you don't want those panels draining backward, through your filter, taking all the scum in there back out through your skimmer. An innocuous little check valve seems like just the ticket. One wrinkle is that the check valve requires something like 1 psi to open, and since the flow is working against that spring, there is a 1 psi drop across the valve at all flow rates. Another wrinkle: yet another spring-loaded valve, in the heater this time, which drops about 5 psi. I'll get to that later.

1 psi doesn't seem like much until you consider that 40,000 gallons pushed through 1 psi at 31% efficiency is 0.935 kilowatt hours. Still not much? The present value is $4343. It's actually a bit worse than that because the constant pressure drop causes the pump to stall at very low speeds, which changes the best operation point to something faster and thus even less efficient.

My last pool (not my design) ran the pump at about 35 psi. As I said, the present value of each psi is $4343, so if this pump had to do the same thing, the present value would be $150,000. That number is so large that you are thinking that it is funny money. It's not. That is this year's electric bill for $3800, and next year's bill for $4000, and the year after's bill for $4200, and so on. It's committed money: if I turn off the pump, the pool turns into a pond and the City folks come by and suggest how to abate mosquitoes. How did I end up with this problem?

Pool equipment is generally designed for low equipment cost, not low energy cost, because the equipment cost is what most homeowners look at. But when we look at cost of energy to drive this equipment, it becomes clear that most pool equipment design is completely insane. The details will come in following blog posts, but in short:

Part	Cost	Pressure drop @ 42 GPM	Power cost	Alternative	Cost	Pressure drop @ 42 GPM	Power cost
Rooftop pressure relief to drain solar panels	$50	8.6 psi for 2-story house	$37,400	Extra 3-port valve and parallel drain to pool	$400	0.1 psi	$430
Gas heater with internal spring-loaded valves (check page 9)	$1800	5 psi	$21,700	Bypass heater with 3" 3-port valve and an actuator	$2050	0.1 psi	$400
DE filter with multiport valve (check page 8)	$700	4 psi	$17,400	DE filter with 2 3-port valves and ozonator	$2100	1 psi	$4,300
100 feet of 2" pipe	$60	1.19 psi	$5,170	100 feet of 3" pipe	$110	0.173 psi	$751
2" check valve	$45	1 psi	$4,300	3" 2-port valve with actuator	$250	0.1 psi	$430
2" 3-port valve	$45	0.5 psi	$2,200	3" 3-port valve	$90	0.1 psi	$430

I've implemented all but one of these on my pool, and it works: I can pump 14 gallons/minute (nearly twice what is required) up through solar panels on my two-story house with 9.5 psi from the pump, and I can pump 40 gallons a minute through the filter at 6 psi. With a fix to bypass the heater (I didn't see that one ahead of time), the pressure drop from circulating water through the solar panels should come down to 5 psi or so.

If you work at Hayward or Pentair and you are wondering how you might fix up your product line to make it more attractive, let me make the following suggestions:

• A $1500 variable-frequency pump with a proper volute, achieving 80% efficiency when operating at 30 gallons/minute and a 5 psi would be a game changer, as it would cut most pool owners' electric bills in half. It would require 3" ports. Please make the main shaft seal ozone compatible.
• Rewrite your manuals to show pool installers how to use 3-port valves to bypass the heater and drain solar panels without spring-loaded pressure relief or check valves. I'll have diagrams for this on my blog shortly.
• A DE filter to go with that snazzy pump, with 3" ports and a valve system with less than 1 psi total drop when clean at 40 gpm. Make the grids ozone-compatible (stainless steel?), and figure out a way to either send the separated air back to the ozone generator or through a catalyst to break down the ozone and nitrogen oxides.
• Introduce or work with Del to produce an ozone generator which has the ozone passively sucked into the intake of the main pump. Alternatively, figure out how to make a low power air pump that forces the ozone into the high pressure water stream after the filter. The current Del air pump is far too power hungry.
• 3" sweep 90 degree and 45 degree elbows, with interiors matched to PVC schedule 40 IDs. There is a trick where you twist the flow as it goes through the corner which might improve losses a bit.
• 3" valves with smooth interior bores. This could be the breakthrough that gets people to take you as seriously as Jandy. The gussets on the valve door interiors now save tens of cents of plastic and cost homeowners hundreds of dollars.
• Since all the big pipework and valves will take up a lot of space, pay careful attention to how all the bits fit together into the space allowed for existing pool equipment pads. Maybe a replacement for the multi-port valve which is made of 3-inch Jandy-type valves would work.
• Fix the pool control systems so that a basic control box:
• can handle 10 valves,
• connects to (and comes with) a flow meter that works down to 10 gpm,
• and has thermistor inputs for solar return as well as intake water, so you can calculate how many BTUs are coming off the roof.

I think that's enough for now. I've been tweaking this post for 10 months, it's time to post!

Pool is filled

Thursday was a big day for all of us. Any passers-by seeing the girls running around in bathing suits for a few days now may have guessed the reason: we plastered and then filled the swimming pool.

Good, Bad, and Ugly

The Good:
I just made myself a goat cheese and apple omelette. Yum! Could have use just a little red onion, and the apple chunks were too large. I will definitely get that right next time.

The Bad:
SolidWorks is crashing on me about every 30 minutes right now. This is not helping me get ready for my presentation tomorrow.

The Ugly:
My eyes. I have red eye, which has all kinds of consequences. Like, getting to stay at home and make myself omelettes. Like, not being able to read small text anymore (should be temporary -- being even slightly blind would truly suck). Like, not being able to make my presentation tomorrow. I sure hope my boss does a decent job.

Bill Gates nails it

http://www.huffingtonpost.com/bill-gates/why-we-need-innovation-no_b_430699.html

His essential argument is:

• We have some agreement on two goals: 30% reduction of CO2 output by 2025, 80% reduction by 2050.
• Some countries will not make much reduction, and some countries, like China and India, will expand their CO2 output quite a bit as their huge populations pass through their own industrial revolution.
• Some portions of our western economies will not reduce their CO2 output easily. (I think this is a minor point.)
• The former goal might be achieved through conservation and improved efficiency.
• The latter goal requires that CO2 output from two sectors, transportation and electricity generation, be reduced to zero. Still more will be required, but this is a baseline.
• Once transport and electricity have been reduced to zero CO2 output, conservation in these areas will not improve our CO2 outputs. This is, for instance, why France doesn't bother subsidizing more efficient electric appliances, as many other countries do -- France's electricity is close to zero CO2, so improved electric efficiency doesn't reduce CO2 emissions.
• Therefore, reworking the economy to reduce transportation and electric consumption does not help towards the 2050 goal. To the extent that it costs money that could otherwise be spent on zero-CO2 electricity and transport, it frustrates progress towards the 2050 goal.

So, what does it take to get to zero CO2 from electricity and transport by 2050? These two subgoals are tied together: transport must be electrified.

Our transport sector currently burns 146 billion gallons of gasoline and diesel every year. In 2050, assuming an increase of 2%/year in transport miles and a fleet efficiency increase from 17 to 23 MPG, it will consume the equivalent of 248 billion gallons of petroleum. If we replace those vehicles with electric vehicles getting 3 km/kWh, those vehicles will consume 3 billion megawatt hours per year. The Nissan Leaf gets 5 km/kWh, so I think an estimate of 3 km/kWh average may be reasonable.

So, the big question raised by Gates' insight is, what can deliver energy like that? To my mind, there are two contenders, wind and nuclear.

The first problem is generation. And the second problem is storage, to cover variations in production as well as consumption.

Here is the generation problem:

The US consumed an average of 470 gigawatts in 2008. The EIA predicts annual increases of 2%/year, so that the average might be 1038 gigawatts in 2050, for the same uses we have today.

The additional 3 billion kWh per year needed to run the electric car fleet, if spread evenly through the year, amounts to 350 GW, which isn't really so bad when thought of in the context of total electric generation. So the grid in 2050 will have to deliver an average of 1400 GW.

1400 average gigawatts could come from 1 million 5 megawatt wind turbines spread over 1.2 million km^2 (at 1.2 watts/m^2). Right now, the US has 1.75 million km^2 of cultivated cropland, so switching US electricity and transport to wind would require a wind farming sector nearly as physically large as our crop farming sector. This is conceivable. After all, 150 years ago most farms had a wind turbine for pumping water. However, 150 years ago that turbine was not the majority of the capital on the farm. These new turbines will cost about $5000/acre, compared with the $2100/acre that farm real estate is currently worth. From an economic standpoint, wind farming would be a much larger activity than crop farming.

The turbines have a 30-year lifespan, so the cost is more than just the initial capital expense. By 2050 all of the turbines installed in the next decade will have worn out, and we'd be into a continuous replacement mode. Cost? $5 trillion in capital outlay for the turbines, another $5 trillion for the infrastructure, and around $160 billion a year (present dollars) for worn turbine replacement.

Here's the storage problem:

The morning commute in any major US city lasts for about 3 hours, with most of the activity in that last hour. The evening commute is longer and more centrally distributed. If we have east-west transmission lines capable of moving most of the commute peak power, we can smooth the U.S. commute peaks into two with four-hour wide centers. Even assuming this transmission capacity, electric consumption during commute hours would be about 500 GW above average.

The current thrust of electric-car research is to improve the batteries so significantly that the cars can be charged overnight and the batteries can provide all necessary power for daytime use. Per vehicle, that's about 18 kilowatt-hours per car, which sounds possible. There is a problem, however: there simply isn't enough material to make these batteries for all our cars.  [Edit: I was wrong, there is.  Lead-acid batteries require 240 kg lead for 18 kWh.  Lithium-ion batteries require 8.5 kg lithium for 18 kWh.]

• Lead-acid batteries would require 60 million metric tons of lead for the 254 million U.S. cars. World production of lead is around 4 million tons/year, and total reserves are around 170 million tons.
• Lithium-ion batteries store 75 watt-hours per pound, and can use about 60% of that (although a five-year life is a goal rather than a deliverable). 18 kWh would require 400 pounds of battery per car, which is physically possible. The U.S. fleet would require 2 million tons of lithium. Total recoverable worldwide lithium is 35 million tons.

The most economical way to store electricity is pumped hydro. Cars could pick up their electricity from metal strips in the freeway. Pumped hydro is at least plausible: the commute surge could be stored by pumping water from Lake Ontario back up to Lake Erie, raising Lake Erie by 60 cm twice a day.

Another way to achieve this goal is with nuclear reactors. Thousands of them. A nuclear electric infrastructure would have five big advantages over a wind infrastructure:

1. It would cost far less to build.
2. It would last 60 years or more.
3. It would not be weather dependent.
4. It would not require secondary storage (still more cost).
5. It would have far less environmental impact (no lakes with tides, no dead birds).

And the biggest advantage of all: it could keep getting bigger.

However, if we are to scale up the existing fleet of 104 reactors by over an order of magnitude, some things are going to have to change.

• Nobody really knows how much it will cost to build the next American reactor. We know that it costs the Koreans and Chinese $1.70/watt, and we know that it used to cost about that much in the U.S. If we build thousands of reactors, the cost will drop back into this range or below.
• Most of the new powerplants will have to be cooled by seawater or air, but not fresh water as is most commonly done today. We do not have enough fresh water to cool thousands of plants. Quite the contrary, by 2050 electric power and waste heat from reactors will be used to desalinate seawater for residential use, as is already the case in Florida and some California municipalities.
• Typical reactor sites will have a dozen or more gigawatt-class reactors, rather than the two or three as is common today. Far from being "extra large", gigawatt reactors are right-sized.
• Either very large new deposits of uranium will be discovered, or most reactors will be breeder reactors.

Bill Gates knows that the nuclear option is going to be the one we eventually choose, and he has a company, TerraPower, developing a new reactor which he hopes will cash in on the $100 billion/year domestic market for nuclear plants. I wish him the best.

Prediction, reviewed

In December 2008 Obama fingered Stephen Chu to be the new Secretary of Energy. This got me in such a good mood that I made a bunch of "predictions", things that might be done right. Maybe these were more along the lines of wishful thinking.

Somehow, all this wishful thinking no longer seems wishful.

• Yucca Mountain shutdown. They did it! The idea of Yucca Mountain was to build a geological repository for spent nuclear fuel. Sounds good, except:
• Nevada didn't want everyone else dumping their waste in Nevada.
• The stuff they wanted to bury was spent nuclear fuel from our light water reactors. This stuff is physically hot! These reactors fission hardly any of their fuel and breed almost as much non-weapons plutonium as they burn uranium. [Edit: it's actually the fission products that make most of the heat, and so it doesn't matter that the reactors aren't fuel efficient.  My bad.]  As a result, the stuff that comes out pumps out prodigious amounts of heat for decades, making it very difficult to cool via conduction through solid rock. Storing it aboveground in air cooled containers next to the reactor is a much better idea.
• As an addendum to the Yucca Mountain thing getting shut down, they've appointed a commission to come up with a new nuclear policy for the US. Per Petersen is on that commission. He is a professor at UC Berkeley who understands the advantages of a fluid-fuelled reactor, and is also doing really good research in how to get there in a practical manner.
• NASA just canned Ares-I, Ares-V, and Orion in favor of spending that development money on multiple private-sector launch systems that will ferry people to the ISS. What a great idea! This is an astounding choice, one that I talked about four years ago in one of my most popular blog posts ever: Why Merlin 2?
• Mandating short-term demand management for air conditioners and other heat pumps. This hasn't happened, but at this rate, I guess I won't be shocked if it does.
• Standardizing recharable batteries. In particular, I had in mind cellphones. While this itself hasn't happened, Europe has standardized the cellphone charger, and that's a good step in the right direction.

I suppose I should have some new wishes. Let's see:

• I'd like to see at least four of those umpteen nuclear plant license applications actually turn into plants being built. I'd like to see hard hats and concrete.
• I'd like to see the Sierra Club or Greenpeace change to a pro-nuclear stance.
• I'd like to see the Federal government "make jobs" on projects that make long-term wealth, not just jobs.

Fountain Advice

So, if I were to design another fountain, how would I do it differently? (This is for you, Diane.)

• 8 inch flow straighteners. There is no sense in messing around with Reynold's numbers. You want it to be around 2000, and that means you need huge internal cross section. 8 inch PVC is actually reasonably easy to get. SCP in Santa Clara has it and all the fittings you need.
  
• Design gimballed nozzles from the beginning. Trying to get this right with careful assembly just did not work, the tolerances are far too tight. I think it can be done with screws between the gimballing nozzle and the glued-in support, so that you could adjust the angle after building it.
  
• Rebar connecting the inside and outside rebar curtains. We have a crack all the way around our hot tub which I'm sure is going to make it's way through the tile some day.
• I would build all the fountain jets to a fixture, rather than just half of them. The fixture worked really well and would have worked even better if I'd designed it to be independent of swelling due to moisture. This can be done -- all the surfaces that locate plumbing have to be on radial lines to the center.
  
• Make the fixture locate a center #4 rebar spike, and drive the center spike at least 18" into the ground, and leave it in place while shooting the gunite. This will give the gunite crews something to locate off when they are drawing their circles. One problem that we had was that we kept re-finding the center of the hot tub, and as a result the circles for the plumbing and the circles for the tile and gunite are not concentric.
  
• I would have the guys doing the gunite get the gunite surface level and ready for tiling. We spent a lot of time levelling that gunite out.

There were also a couple of things we've learned about the tiling, which would have saved us a bunch of time had we known it a year ago.

The glass tile is 1/4" thick, and can be set with just 1/8" of thinset, but this isn't the stackup you want. There are two problems: the thinset shrinks, a lot, as it cures, and this tends to bend and eventually break the tile. Also, the plaster guys want to be 5/8" thick, not 3/8" thick. They can feather down to 3/8", but they don't like it, as explained below.

So, you want to put down on the gunite 1/4" of some kind of low-shrinkage mortar, and screed it so that it is flat. This is the stuff that is going to take out all the uneveness in the wall. However, you can't be sure it's going to stick really well to the gunite. So, the stackup we used under the last mosaics ended up being:

• 2 coats of Hydroban, sticking out at least 1" past any of the rest of the stack. This forms a structural watertight barrier. The principle issue being protected against is water leaking through the cold joint between the plaster and the tile, and then leaking into the gunite from there. Hydroban is expensive, but only comes in 5 gallon buckets, which is enough to cover a ridiculously large area. I think they are trying to make sure you use a lot.
  
• Some thinset, as thin as it can be, to adhere the mason mix to the hydroban.
• 1/4" mason mix (either "deck mud" for the tile on the pool bottom, or "fat mud" for the tile on the walls), screed to be dead flat.
• After that all sets up (ideally about 4 hours so it gets a chance to shrink, but isn't fully hard, think about covering it with plastic to keep the water in), a super-thin layer of thinset on both the mason mix and the back of the tile.
• Blue tape out the wazoo for anything on a wall.
  
• Then cut the stiff but not yet really hard mason mix away from the edge of the tile. We never let the mason mix set up so hard that it was sticking to the hydroban tightly, so this was pretty easy to do without nicking the hydroban.
  

On our dam wall, we had to build up the wall top with an angle to hold our teflon strip. The easy way to do this would have been to just do it with wall mud, screed with one of those adjustable angle things running along a strip screwed to the side of the wall.

Now back to the reason the plaster guys want to put down 5/8" material. For any kind of exposed aggregate surface, they shoot the mix, then trowel it. The troweling is usually done (on a smooth plaster finish) to bring the "cream" to the surface, but for an exposed aggregate surface they are using the side effect, which is to compact the aggregate below the surface. Then, when they wash away the surface, they expose more tightly-packed aggregate. Since cement but not aggregate will erode from chlorine attack and mechanical erosion, it's better to have a surface which has more aggregate.

The reason they don't simply mix more aggregate into the mix before they shoot it on the wall is that, when the aggregate and sand grains are randomly oriented, they simply can't pack densely enough. If you subtract sand/cement/water, you don't end up with more aggregate in the as-shot mix, you end up with more air. And air is no good because the plaster has to be watertight (and dense and strong). Once the mix is on the wall, they work it with the trowels, which helps settle the aggregate and sand grains together more tightly. This is why the quality of an exposed aggregate surface has a lot to do with the skill of the guys doing it.

In looking at the samples provided, it's clear to me that most folks aren't actually attempting to get a maximum packing of aggregate, and I don't understand why. Why don't they mix larger and smaller aggregate together, so that the small aggregate packs in the spaces between the larger aggregate?

Pocohontas Retold

Spoiler alert: I discuss the movie Avatar below.

When I read the Pocohontas story to my kids (we have the Disney version), we usually have a little discussion when we get to the page where Pocohontas attempts to dissuade her father (the local Indian chief) from starting a war with the settlers. The kids are interested in the idea that both people are trying to do the right thing, but they have completely different ideas about what the right thing is.

For those of you not familiar with the story, Pocohontas has fallen in love with a mercenary on the voyage (John Smith), and the two of them want to establish peace between the settlers and the natives. The book suggests that peace involves the settlers staying in North America. Powhatan, her father, is assembling a war party to drive the settlers away.

We can look back in history to better understand who was "right".

• As the book makes clear, a war between the settlers and the Indians is going to lead to many Indian casualties, since the settlers have guns and the Indians do not. Furthermore, most of the settlers are not intending to do harm to the Indians, as they've been told they are settling land that has no ownership yet. Pocohontas' efforts end up saving many well-intentioned people's lives.
• These same settlers would probably understand that, had they landed anywhere in England and built a village where they landed, they would be summarily evicted by whomever owned the land they were on. The racism here is lightly touched on in the book, but it's helpful because it's pretty easy for the kids to see how convenient it is for the settlers to suppose that nobody in North America owns anything yet.
  
• I usually tell the kids what little I know of the Mauri, the indigenous people of New Zealand. As I understand it, they immediately made war with white folks who arrived. I suspect that the Mauri were territorial in a way that worked better with the White conception of property, and because of that Mauri today have a significant representation in the New Zealand constitution and legislature, and own very large amounts of New Zealand's real estate. I expect many Native Americans would prefer the Mauri outcome to their own.

I recently went to see Avatar. It's basically the Pocohontas story, but the ending has changed and the natives switch from the Pocohontas to the Mauri approach. The change comes from two differences:

1. The Na'vi are territorial. They have a few specific high-value trees. My understanding is that most of the North American natives had a much less specific sense of property.
2. The movie has the natives resisting under human leadership, which is interesting to think about. It seems a bit condescending (especially the bit where the human, after 3 months of training, is outperforming the best of the natives), but historically North American natives really did not grasp the nature of the European threat fast enough to organize a massive resistance in time, and it seems at least possible that a charismatic European might have communicated the continent-level consequences of the European idea of property to enough of them to organize a resistance.
   

Although the movie doesn't make it clear enough, guns are a big advantage, but a multi-year supply line is an even bigger disadvantage. Although some of the dialog is a bit trite, I think the story is probably going to be a useful place to start interesting discussions. Hopefully they'll have some story books out at some point, because the PG-13 movie is far too violent for my kids to watch.

I once asked a friend who is a lawyer if all property rights, at least in North America, trace back to peace treaties of some kind, or if some (particular the French claim to the center of the continent that was then sold as the Louisiana Purchase) are based on bald assertions of authority without even a war. I never did get a decent answer.

If, in reading this post, anyone is wondering if I'm willing to cede my house to a Native American, the answer is no.

Powered Roadways

If it weren't for the battery problem, an electric vehicle could be a fairly reasonable vehicle today: electric motors are powerful, small, and cheap enough, etc. There are two parts to the battery problem, getting enough power and storing enough energy. Both can be solved by delivering power to the EV from the road. This has been considered many times before, and there are electric street cars that do it in Bordeaux.

The usual idea, however, is very expensive because

• most sections of roadway or railway see little traffic and so the benefit of the high-cost infrastructure is spread over few vehicles.
• the third rail power delivery system is made safe by expensive grade separations, fences, or electronic switching
• the vehicles are very specialized and aren't built in large numbers.

So, to the extent that I'm advocating a new idea, it is... electrify urban highways. By which I mean, install a pair of metal strips flush against the paving in one of the lanes, such that ordinary cars aren't affected, but electric cars can lower a suitable pickup onto the strips and receive a few dozen kilowatts. Both the power and the energy storage demands on an electric vehicle's battery are dominated by the demands of highway operation.

Urban freeways are quite unusual as roads go.

• They see quite a lot of traffic: The San Francisco Bay Bridge moves 270,000 vehicles a day across 10 lanes = 1 vehicle every 3.2 seconds over a 24-hour average.
• They see quite a lot of the traffic: 24% of all traffic is on interstate highways, and I'll guess that most of that is on urban interstate highways.
  
• They are short: in the entire US, there are just 15,300 miles of interstate highway in urban areas (same link)
  
• They already have limited access. The safety hazards of a high-voltage electrical system out on the road are relatively minor compared to the existing vehicles using the roadway.
  

I don't have sources to verify the following claim, but I'm fairly sure that in many urban markets, most trips over 10 miles include some freeway. So, if the freeways in your urban area (e.g. Los Angeles or the Bay Area, or both) were electrified, you could make trips anywhere in that area in an electric car with a battery range of just 10 miles.

And, if all we want is 10 miles of range, with no need to deliver dozens of horsepower for minutes on end, existing battery technology is good enough.

The usual counterargument to big infrastructure is that it costs too much. However, electrifying freeways does not because the freeways are just not that big. Consider the Bay Area:

• 300 miles of freeway
• 7 million cars

If, over 10 years, we got to 10% of the cars being EVs with electric pickups, that would be 700,000 EVs, or, one for every 26 inches of freeway. Can 26 inches of roadway be upgraded for less than the cost of equipping an EV with a huge battery? Definitely.

There are many schemes for electrifying roadways, and some are quite complex. Although a simple pair of flush steel rails at 1000V is probably a reasonable implementation, it might be easier to sell to the public if the rails were safe enough to be touched by hand. This too is possible.

Imagine each rail is a hollow box, insulated on three sides, but with a nonmagnetic and top surface. Inside the box is a lightweight, magnetic, conductive cable (probably aluminum and steel), with a small gap between it and the underside of the top surface. The conductive top surface is broken at short regular intervals by an insulator. The bottom of the rail is probably a large conductor for moving electricity thousands of feet.

Without a magnet, the top surface is not electrified, and you can place your hand on it safely. The car's pickup would have a magnet which would ride on the strip, picking up the lightweight inner cable slightly, so that it contacts the top surface and conducts to the car.

Other variations would have a magnetic top surface with a flux gap, such that flux going from one side to the other shorts through the cable and picks it up that way.

System Design for Martha

I need to buy a new computer for Martha.

• Must drive a flat panel display
• Must accept data from a FireWire miniDV camera
• Must have a DVD burner
  
• We have an ancient parallel-port printer.... which would be nice to use.
  

I could buy a Mac Mini. The Mac Mini has the FireWire interface and DVD burner. However, it will never work with that printer (a replacement will cost $150). The graphics would be much better than any mini-ITX integrated graphics I'd get. We'd get the 2.53 GHz, 4 GB memory, 350 GB version, $830. A VMware executive will cost another $70. The whole thing will come in a nice little case and make very little noise, and I will have even less idea how the software works than I do with the PC.

Or, I could build a PC. I'd get a 3.16 GHz Intel E8500, 8GB memory, 500 GB hard drive. I can get a FireWire card and a DVD burner, and a motherboard that sports a parallel port. Martha will be happy that I didn't make her figure out a Mac (more to the point, how to run PC-only software under VMware on the Mac). Vista will almost certainly never work with the printer, and so I'll still have to get a replacement anyway (a wash at $150). Even crammed into a mini-ITX case (with some risk it will not all fit in the case), it'll cost $875. The Mini idles at 14 watts, and any PC I build will idle at 35 watts. The 20 watt difference, over 5 years of 24/7, costs an extra $350.

Update: Since Martha figures she's going to be stuck with the sysadmin, she opted for the PC, to avoid learning about VMware, Boot Camp, or any other virtualization. If we could order the Mac Mini with Windows preinstalled under a supervisor, such that I could have told Martha that she could simply install any Windows programs or drivers, then she probably would have gone for that. Oh well.

Engineering is Plumbing

http://credentiality2.blogspot.com/2009/01/engineering-is-plumbing-not-math.html

99% of what I do is plumbing.

-Iain

Quick pool status

Patio around the pool is mostly in. Hopefully today they will finish off the corner around the pump vault.

Saturday I had hoped to install the last of the tile mosaics, but instead I found the remaining big Orca cracked in the center, and the north side dolphins had cracked as well. We cut them all off the wall and will reinstall the lot next weekend.

The tilework around the hot tub was fairly tricky. Here's an example of a three-way miter. The tile guys kept looking at me like I was cuckoo. As I explained, you cut it by cutting each of the three two-way miters. It's actually pretty straightforward if you just do it.

The hot tub as a whole. In the background, you can see the breaching Humpback mosaic, along with a portion of the Orca mosaic. The Orcas are the ones that have been giving me so much trouble.

Chuck DeVore nails it

Relative Risk: Global Warming and Imported Fossil Fuels vs Nuclear Power

It's from last year, but Representative DeVore perfectly summarizes the environmental aspirations and political logjam in California, and points out that a voter initiative is possibly the only way to cut through the logjam.

Anniversary of Lezak's Wild Ride

For the first anniversary of Jason Lezak's incredible come-from-behind finish in the Men's 4x100m freestyle relay, NBC has full-race underwater coverage of the race: http://www.nbcolympics.com/video/player.html?assetid=0812_hd_mul_au_ce493&channelcode=sportsw (Watch the link in Firefox, because it doesn't work in Chrome.)

I've written about this incredible race before, but this footage shows in more detail some of what was going on during the race. Although the Australians were doing well at the beginning, by the last lap it boils down to the French and the Americans. America's Lezak takes 29 strokes on the way out, versus France's Bernard Alain, who takes 32. Not much difference, although it is already interesting that the taller Frenchman is taking more strokes.

On the way back, things change. Lezak takes 34 strokes, and Alain takes 42. Something happened to Bernard's stroke on the way back, something that didn't happen to Lezak.

Looking at this video again, it's clear that Jason has a very different stroke than Bernard. Maybe it's because he breathes only to his right, and does so on every stroke. But I think there is more going on than that. From the top camera, watch Jason's head. It's going up and down a lot more than Bernard's. Watch his back. His back is pumping up and down more than Bernard's as well. From the underwater camera you can see that Jason is pumping the left side of his body up and down. Bernard goes straight through the water, which looks more efficient, but I don't think efficiency is what is going on here. I think Jason is pumping water backward with his whole torso, like in the butterfly.

One other note: Jason is blowing so much air under his body that his left hand is travelling through that air. Grabbing air cannot be helping propulsion, but it's possible that by getting that air under his body he is reducing his drag.

I'm pretty sure Jason Lezak has found a better way to swim the freestyle.